The present study was intended to provide perspective, albeit less than unequivocal, on the research of Lynn (2010) who reported higher IQs in the northern than southern Italian regions. He attributes this to northern Italians having a greater genetic similarity to middle Europeans and southern Italians to Mediterranean people. Higher regional IQ…

Comparison of the mental status of 30 subjects with Down's Syndrome mosaicism and 30 matched subjects with trisomy 21 Down's Syndrome found that the mean intelligent quotient of the mosaic Down's Syndrome group was significantly higher and that this group showed better verbal abilities and more normal visual-perceptual skills. (Author/DB)

Data from the General Social Survey (GSS) collected in the years 1990-1996 are examined for the relationship between fertility and intelligence as measured by vocabulary. The results show that the relation between fertility and intelligence has been consistently negative for successive birth cohorts from to 1900 to 1979, indicating the presence of…

The question as to whether males and females have different kinds of intellectual abilities is addressed. The evidence that there are some differences in cognition and perception between men and women is reviewed. (KR)

Genetic effects on specific cognitive abilities as distinct from those on general cognitive ability were studied in 302 pairs of twins (some reared together, some apart) from the Swedish Adoption/Twin Study of Aging. Overall, results showed significant genetic influence on specific abilities independent of influence on general ability. (SLD)

Argues against the presence of dysgenic trends for IQ on the basis of absence of change in the differences between various groups. Illustrates this with an example of the numbers of children born to Black and to White women at different educational levels. Discusses the effects, mechanisms, and implications of dysgenesis for IQ. (MMU)

Platelet serotonin (5HT) levels of 5 autistic subjects (ages 16-37) who had siblings with either autism or pervasive developmental disorder were significantly higher than levels of 23 autistic subjects without affected siblings. Autistic subjects without affected siblings had 5HT levels significantly higher than 10 normal controls. Sex, age, and…

Word recognition data from identical and fraternal twins and siblings (N=172) indicated that the phonological coding deficit of children with reading disabilities was highly heritable. Orthographic coding was not significantly heritable. Poor readers with low IQs were superior to similar reading but average IQ readers in phonological coding.…

This study of 640 twins with reading disability and 436 controls (mean age 12) examined external validity of the distinction between specific reading retardation and reading backwardness, in 3 domains: genetic etiology, sex ratio and clinical correlates, and neuropsychological profiles. There was no evidence of differential genetic etiology of the…

Examines national data sets of cognitive scores for intellectual dysgenesis by considering race, socioeconomic status, and ability-related changes in test scores over time. The analysis did not support the dysgenic hypothesis; however, it indicates a convergence of the various segments of U.S. society. (MMU)

Pychologists, educators, and others have challenged the idea of a fixed IQ. This book uses recent research and earlier discoveries to argue that intelligence is not genetically set. Noting that the idea of learnable intelligence reflects the belief that intelligence can be taught, the book outlines a theory of learnable intelligence, including…

Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…

Pseudoscience, or the process of persuasion by establishing a pretense of scientific discovery, is examined in this book in an effort to dispel false notions about the validity of various measures of intelligence and the correlations of genetics to mental ability. The history and development of concepts related to hereditary intelligence and…

This paper critically examines the portions of Arthur Jensen's books, "Genetics and Education" and "Educability and Group Differences," that concern Barbara Burks' 1928 study of adoptive families. Jensen cites the low correlations of children's IQs with measures of home environment from Burks' study as evidence that environment…

This final report reviews the second phase of a life-span study of boys with fragile X syndrome (FSX), the most common known inherited cause of mental retardation. Males with the syndrome are more severely affected than females and in males, delays are usually evident in all the developmental domains, although cognitive and communication skills…